Catalyst
by chelseyb
Summary: For she was his catalyst, even in death. Oneshot. Rating for sexual situations.


**Disclaimer:** Harry Potter isn't mine. If it was, I would be making money, not publishing things for free.

**Author's Note:** It would only let me put two categories, but there is definitely angst in this. Warning: contains underage sex and character death.

A good song to go with this fic is "Eternal Smile" by Long Story Short.

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><p><strong>Catalyst<strong>

Harry Potter was a dead man.

And for once, the person threatening his life wasn't Voldemort, in any way, shape, or form. No, it was a clumsy, hair-changing, occasional-pig-snout-sporting Auror. Because Harry Potter had just been caught eyeing the extremely attractive body of said Auror, and he was sure that twenty-something Metamorphmagi did not appreciate the goggle-eyed stares of barely fifteen-year-old boys.

Harry waited for the amused smile to drop from her face. It was that smile, combined with a wink, that had led Harry to this very point. Harry didn't often consider himself normal, but one thing that was normal about him was that like any other teenage boy, he was quick to notice a pretty girl. Or woman. And in the kitchen of the Dursleys' home on Privet Drive, he had definitely noticed a pretty woman. But it wasn't until she skipped past him in the hallway when he first entered Grimmauld Place and flashed that amused smile, followed by a cheeky wink, that Harry lost his head. Or his heart. Whatever it was he'd lost, it turned him into a staring, stammering shell of himself in her presence.

It wasn't his fault that she was always around. Or that she preferred low-slung jeans and t-shirts that pulled up whenever she stretched. It wasn't his fault that he had picked up on a very citrusy scent when she walked past him and couldn't look at a piece of fruit without getting turned on. It wasn't his fault that she once fell asleep on the sofa in the drawing room, and he thought he'd never seen anything more beautiful. And it wasn't his fault that, not for the first time, she spent two straight hours last week talking to him and only him.

Today's incident definitely wasn't Harry's fault. Mrs. Weasley had had them pair off to tackle several rooms in one day, and Tonks hadn't so much as asked Harry to join her as she had simply dragged him out of the room, claiming "Harry's mine!" And so Harry had spent the entire afternoon with Tonks alone, chatting as they cleaned the library. Well, Tonks chatted, and Harry tried to untie his tongue. To her credit, Tonks had a way of pulling Harry into the conversation, inquisitively asking questions about his life and his interests. And then it happened.

"Hotter than the Hogwarts dungeons on a June day, isn't it?" she said cheerfully, pulling off her short-sleeved button-up to reveal a form-fitting tank top. And then she reached up to the highest bookshelf, replacing some loose books.

Harry nearly fell over. Vivid pink locks hung in loose curls, just brushing her shoulders. Her top was purple and clung easily to her breasts, rising up and down in even breaths. It had gotten tugged up above her navel, revealing light, peach-colored skin all the way down to where her jeans hung off her hips, curving nicely around her bum. Then Harry looked up, and Tonks was staring at him with an amused smile.

Harry Potter was a dead man.

Tonks stepped down off the chair she was standing on and walked towards him, still smiling. Harry tried to back up, but as he was already in a corner, he only managed one step before he felt the wall at his back. Tonks came closer and closer, her smile widening. Harry swallowed, looking above her head, afraid to meet her dark eyes. When she was close enough that her boots met his trainers, she stopped.

"Harry Potter, you naughty boy," she said in a soft, silky voice. "Are you checking me out?"

"I – I ... maybe," he stuttered, surprising himself with his honesty.

If possible, her smile grew even more amused. "Well well, what are we going to do with you?" she asked slowly.

"I think I'm beyond help," Harry managed to get out.

"Do you know what I think?" Placing a hand on either side of him, Tonks leaned forward until her lips were at his ear, filling his nostrils with the not unpleasant scent of a familiar citrus smell mixed with a hint of sweat. "I think you might just drive me crazy," she whispered, her breath tickling him. Harry stopped breathing.

Then she pulled back, turned, and walked away. "You're covered in dust, you know," she said, tossing him a glance over her shoulder. "Reckon I look the same. Think I'll hit the showers now." She winked at him before she left, and Harry waited exactly thirty seconds before sprinting out of the room, determined to find his own bathroom to lock himself in for the next ten minutes and praying no one saw him before he reached it.

**oOo**

"Harry Potter," Tonks said, sauntering into his bedroom. "What are you doing?"

"Packing," he replied, holding up his new books.

"That's right," she said, leaning against the doorframe. "You go back to Hogwarts tomorrow, don't you?"

"Yeah," Harry confirmed, tossing the books in his trunk and daring to look at her.

"That's too bad," she said carelessly, examining her fingernails. "It'll be dull around here."

"There's always Christmas," he offered, and when she looked at him, raising her eyebrows as a smile tugged at the corners of her lips, Harry just gazed at her.

"You're very tense." Tonks lightly drew a hand over Harry's shoulders as she sat on the bed next to him, making him catch his breath.

"Well, a pretty girl does that to a bloke," he said, wishing his voice hadn't cracked on the last word.

Oh no. There was that smile, like she'd never seen anything more amusing. "Turn around, face that way," she said gesturing. Harry did as he was told, wondering what she – oh dear Merlin, she was massaging his shoulders, her fingers expertly rubbing each and every single knot of tension. This made Harry think of other things she could do with her fingers, and he squirmed.

"Be still," she said gently, her tone indicating someone used to be obeyed. "Am I hurting you?"

"Not at all."

"So ..." she said, drawing out the word tantalizingly. "What pretty girl has you all worked up? Is it Ginny?"

"No, definitely not. Ginny looks like pictures of my mother."

"Yes, I could see how that would be a turn-off. Is it Hermione?" Harry felt the bed shift as she moved.

"No, Hermione's just my mate."

"Ah, the friend zone." It sounded like she was about to laugh. "Is it Hestia? She was here for the meeting earlier, and I know for a fact that Sirius, for one, would like her to be around more often."

"No, it's not Hestia."

"Well, who could it be, then?" The bed shifted again, and Harry froze when he felt her breasts against his back. She ceased kneading, choosing instead to run her hands over his chest. Her hair grazed his ear, and when she spoke, her breath was warm against his cheek. "Is it _me_, Harry Potter?"

"Maybe," he said shakily, afraid to break the spell she had over him.

She laughed. "Confidence, Harry. Just say yes or no." Then, so softly Harry almost thought it was a dream, she brushed her lips against his cheek. "It's such a shame."

Harry remained absolutely still as she left. She kissed him. Tonks kissed him. And – wait, it was a shame? His wits returned from their outer orbit, and he found his voice. "What is?"

She paused in the doorway and sent him that infernal wink. "That you're only fifteen."

**oOo**

Over the first term at Hogwarts, Harry thought he did a pretty good job at forgetting about Tonks. With Quidditch and Umbridge and the DA to fill his days, when Christmas came around he was confident he could now handle a conversation with her without stuttering and having to remind himself every five seconds not to stare at her chest.

All of which was proven wrong the first time she winked at him at Grimmauld Place. By the time New Year's Eve arrived, Harry was going out of his way to avoid her amused smile and spending increasing amounts of time locked in his room. When Harry realized that somehow they were the only two left in the drawing room late that night, he began to panic and headed for the door with a mumbled excuse. Moving quicker than he thought possible, Tonks beat him to the doorway.

"What's gotten into you, Harry Potter?" Tonks asked, looking, as she always did, ever so amused.

_You. Dirty thoughts. My inability to control my own hand._ "Nothing, just tired," he lied.

"If you want to be a good Auror, you need to become a better liar," she said, walking into the room. Harry backed up, but she followed. His heart started to beat faster, and he wondered if she was deliberately trying to kill him.

"Who said I want to be an Auror?" he asked, looking anywhere but at her face.

"No one," she said cheekily. "But I think you'd be a fantastic Auror."

"You do?" he asked, stunned into looking at her. Her eyes had a mischievous glint, but she looked sincere.

"Oh yes," she said, smiling. "All you need is a bit of training and a backbone." She was still heading towards him, and Harry continued to stumble backward until he felt a chair hit the back of his knees. He sat, still withdrawing from her heady presence, and Tonks actually leaned over to face him, a hand on either arm of the chair.

"A backbone?" he repeated with some difficulty as his mouth had gone suddenly dry.

"Yes, a backbone." She gently tugged his chin up. "For instance, if you like a girl, you ought to say so instead of simply watching her throw herself at you. Or better yet, just do something about it. After all, actions speak louder than words."

This wasn't happening. This was _not _happening. This was a dream. Any second now, Ron would snore and Harry would wake up, and he would be forced to once again take care of himself and hide his burning face at breakfast. And then her lips were on his, Tonks was kissing him, and it was most certainly not a dream, for no dream ever felt this real. Her lips were soft and tasted like strawberries and then her tongue was in his mouth, Tonks's tongue was caressing his, and Harry gripped the arms of the chair so tightly he thought he would break them.

She pulled back, leaving Harry breathless. "You know, like that." Harry was thrilled to see that she was flushed. She wanted this as much as he did, he realized, and with that he grabbed her waist and pulled her into his lap, kissing her again and again. She made a delighted noise in the back of her throat and responded with enthusiasm, allowing his hands to roam her curves as she pressed herself against him. Harry squirmed as he realized his body was betraying him, but she didn't seem to mind. "We can leave this PG, or we can go to my room," she mumbled against his lips.

"Your – your room," he forced out, still unable to believe that he was making out with Tonks, that as long as he could keep it together he might in all likelihood be doing something else with Tonks. He was lightheaded and dizzy.

Tonks grabbed his hand and pulled him out of the room, running up the stairs without relinquishing her grip. She looked back at him on one landing, and a smile lit up her face, making Harry ache. When they reached her room, she pushed him in and closed the door behind her, locking it as she did. She leaned against the door, eyeing him up and down with obvious desire, greed mixing with amusement in her expression. She wore a ratty, green Weird Sisters t-shirt that Harry hadn't paid much attention to until she pulled it off as she walked towards him, working her way out of her jeans as well.

"Can I ... touch ...?" he asked as she stood in front of him in nothing but her bra and knickers, looking absolutely beautiful.

"Of course you can," she said, laughing as she wound her arms around his neck. "That's kind of the ... oh. _Oh._" Tonks pulled away and sat on the bed. "You're fifteen. How could I forget? You've never done this before. This is not right. Oh Merlin, I am so sorry, Harry."

Harry sat next to her. "Wait, no, Tonks. I don't care. Please, I ..." If Tonks stopped him after going this far, Harry would just about scream with frustration.

"Fifteen," she repeated, caressing the side of his face. "It really isn't fair, is it? I shouldn't be having impure thoughts about a fifteen-year-old. I thought I was over that, and then you come along at Christmas and I'm right back to where I started."

"I want this, you know," he said urgently. "I don't care how old you are. I can handle this."

"Can you?" she asked, a trace of amusement returning to her face. "Can you be with me tonight and then remember that I'm twenty-two, off limits until you leave school?"

"I absolutely can," he breathed. "No going weird on you."

Tonks laughed and stood up, pulling Harry with her. "There's that backbone. You're going to do great things in life, Harry Potter, starting tonight." She tugged his shirt off and began exploring his neck and chest with her lips, making him groan. "Just so we're clear, you know this is a one-off, right?"

"Just for tonight," he promised. She sighed, and there was such relief in that sigh that Harry would have been completely turned on even if she hadn't been half-naked.

"I seem to remember something about touching," she said, working the zipper on his jeans. Harry cautiously lifted his hands to her breasts, feeling how they fit into his hand. Without speaking, Tonks loosened her bra and let it fall to the floor in one fluid motion. Making sure his hands weren't shaking, Harry continued his gentle massage, marveling at the softness. Sneaking a peek at her face, Harry saw that Tonks had her head tilted slightly back, eyes closed and lips parted. Emboldened, Harry replaced his hands with his mouth, and she moaned.

"Is that good?" he asked.

"Very," she said. "Hold on." She found her wand and shot a spell at the door of her room. "Silenced. Don't want Remus next door thinking I'm having a jolly good time by myself in here. You can keep going ..."

Harry did so until he felt her hands run across his bum, which, he realized, was bare somehow. He took a step back and saw that she had somehow removed both their pants without him noticing. Harry had difficulty swallowing; as beautiful as he had thought Tonks was earlier was nothing compared to how she looked completely naked. Feeling like he was about to explode, he pulled her to him forcefully, kissing and groping desperately.

"Harry Potter," she said, tenderly yet firmly, and he froze. "We're going to do this properly or not at all."

"Prop – properly sounds good," he said, embarrassed. "I just, I don't know what I'm doing."

"Oh, don't worry about that," she said as she led him to the bed. "I do."

They continued to snog and explore each other as he climbed on top of her. When Harry finally entered her, he let out a ragged gasp and thought his heart stopped beating. He had never imagined anything could feel this good, feel this intense, and then she _moved_. Oh sweet mother of Merlin, Harry could have been done in about ten seconds flat, but he wanted her to enjoy it, too, and so he tried his hardest to keep his movements slow and shallow. When she hooked her legs behind his arse and tugged forward, he was encouraged.

"Good?" he managed to get out.

"Oh yes." He was gratified to hear that her voice was strained and hoarse. "You're doing great."

The motion of his hips required all of Harry's concentration and so he stopped kissing her, but she certainly didn't seem to mind, her whispers of encouragement and direction giving way to moans and unintelligible words, which he could barely hear through his own noises. Soon, it all became too much for Harry to handle. He was sweating and trembling and overcome by the urge to shout out that he loved her. His thrusts were deeper and faster, and it was all starting to become a blur.

"Tonks, I –" he forced out.

"Mm-hmm," she moaned, her fingers digging into his back as her heels dug into his legs. "Please, Harry."

It was all he needed, and when it seemed like the sun exploded in his eyes, a yell tore from his throat. He recovered in time to see Tonks throw her head back, her hair morphing into pure white as she, too, cried out. It was the most erotic thing he'd ever seen. He lay on top of her, unable to move as they panted in sync. Eventually he felt he was making her uncomfortable, and so he rolled over. Tonks came with him and curled up on his side, resting her head on his shoulder.

"Tonks, that was ..." he paused, searching for the right adjectives.

It was unnecessary. "Believe me, Harry Potter, I know. I was there, too."

He laughed. "Yes, you were, weren't you?"

They lay together for some time, Tonks tracing his chest and Harry playing with her hair as they talked in low voices. Finally Harry slipped out from beneath her, feeling like it was time to head to his own room. She lay on her side, watching him dress. A sheet just barely covered parts of her, and Harry wanted nothing more than to climb back into bed with her. When he was dressed, he sat on the edge of the bed again, and she sat behind him, resting her arms and chin on his shoulders.

"What do we do now?" he asked softly.

"You go your way and I'll go mine," she answered. "Look me up the second you graduate from Hogwarts."

"What am I supposed to do in the meantime?"

"Do whatever you want, Harry," she said sincerely. "Play Quidditch. Work hard on your OWLs and NEWTs if you really want to be an Auror. Take the pretty Ravenclaw to the broom cupboard on the fifth floor. Have fun!"

"And what will you do?"

"Oh, I'll be waiting for you to walk out of the Entrance Hall for the last time, Harry Potter."

**oOo**

"_Avada Kedavra!" The green light shot from Bellatrix's wand and hit directly in the middle of Tonks's chest. Her own wand, in the middle of casting a spell, dropped from her lifeless fingers as she fell to the stone steps, the light draining from her eyes, her face frozen forever in the same smile._

Harry had seen it happen, and Harry couldn't stop it from replaying in his head. It had never occurred to him, as he rushed off to help Sirius in the Department of Mysteries (or so he thought), that anyone else would be harmed. It had never occurred to him that a single jet of light could extinguish the life from so joyful a person. It had never occurred to him that Tonks wouldn't be there when he finished school, just like she'd told him.

"YOU WEREN'T SUPPOSED TO DIE! I WAS GOING TO WAIT FOR YOU!" Harry raged in Grimmauld Place, where he was spending the summer with Sirius after a short stay at Privet Drive. He had held it together for weeks, but now he was in Tonks's old room. She had left her things there like she planned to return. Harry's eyes burned as soon as he saw a pair of her clunky boots on the floor, but it was the sight of a ratty, green Weird Sisters t-shirt on the bed that made him snap.

He grabbed the shirt and flung it at the wall. "YOU MADE ME LOVE YOU, AND YOU LEFT ME! WHY WOULD YOU DO THAT?" He kicked one boot and grabbed the other, throwing it at the door, making it shut with a satisfying slam. "HOW COULD YOU? WE WERE SUPPOSED TO BE TOGETHER!"

"Harry!" Sirius said, rushing into the room. "What's going on?"

Harry stared at him, his chest heaving. "I loved her." He pointed. "I loved her on that bed, and she said to wait until I left Hogwarts. I still love her, and I don't want to anymore!"

"Yes, you do," Sirius said quietly. "That's why it hurts."

"NO I DON'T!" Harry roared, trying unsuccessfully to keep the tears at bay. "I don't want to feel this way anymore, I want to forget her, I want this to stop hurting!"

"I know you do, Harry, and so do I," said Sirius thickly. "But you don't want to forget her, ever."

**oOo**

Harry never told anyone but Sirius about Tonks. Sometimes, when he was alone, he talked to her, occasionally imagining her responses. He was sure his friends would have said he was crazy, but he would have told them it was the only thing that kept him sane. As trite as it sounded, Tonks, a woman so full of life herself, wouldn't have wanted him to fall apart, and sometimes it was only her memory that kept him going.

"You told me once that Aurors follow their gut instincts. Yesterday I discovered that Draco Malfoy is a Death Eater. Ron and Hermione don't believe me, but I've got to find someone who will. If you were here, I know you would."

"Dumbledore is dead. I don't know what to do, Tonks. I always thought he would be here to lead me. But I always thought you would be here, too."

"Ron left today. He left Hermione and I to finish this on our own. I'm afraid she's going to leave, too, and I can't do this by myself. I want to tell him that I could never love Hermione like he thinks I do, because I gave my heart away a long time ago."

"It's over, Tonks. I defeated Voldemort. We could have used you in the battle."

After the war a memorial was erected at Hogwarts, and the survivors of the Order made sure all the deaths were included, not just those in the Final Battle. Harry liked to trace Tonks's name as he talked to her. The horrors of the war threatened to overwhelm him at times, but remembering her words, he set goals and allowed himself pleasure in his accomplishments. For she was his catalyst, even in death.

"Here I am, Tonks. I didn't finish Hogwarts, but I think you would agree hunting Horcruxes made up for that. I'm of age and out of school. Where are you?"

"I start Auror training tomorrow, Tonks. I don't know who's training me yet, but I'm sure they won't be as good as you would have been. I miss having you around to tease me."

"Well, I did it. I'm an Auror now. I could almost hear you at the ceremony. 'I told you you would make it, Harry Potter.' You were right."

"They made me Head Auror. I can't believe it. I'm only 27! Ron wants to take me out tonight to celebrate, but the only one I want to celebrate with is you."

"You told me to wait until I finished Hogwarts. I know that technically I never did finish, but I've waited for you my whole life. Please come back to me, Tonks."


End file.
